8th Grade · Functions
Function
8.F.A.1
Definition
A rule that assigns to each input exactly one output. No input may produce more than one output.
Teach it
Where it is taught, with guided notes, practice, homework, an exit ticket and an interactive Teacher Deck.
Examples
- f(x) = 2x + 1: input x = 3 gives exactly one output, 7.
- An input pointing to two different outputs is NOT a function.
Key rule
Every input must map to exactly one output for it to be a function.
Memory hook
One input, one output — always.